fix(pegas-memory): web fetch SOCKS5h proxy fallback + stale_guard supported double-count fix

- ingest.parse_web: direct fetch; on block/timeout retry via socks5h://127.0.0.1:1080 (SOCKS_FALLBACK_PROXY); raises ValueError if both fail.
- config: add SOCKS_FALLBACK_PROXY default (socks5h://127.0.0.1:1080).
- self_improve.stale_guard: supported LLM verdict now sets status_change='supported' (authoritative), no fallthrough to age fallback -> no double-checked/skipped_no_source.
- README: document auto-fallback.

pegas_memory/self_improve.py

@@ -198,6 +198,8 @@ def stale_guard(conn, *, atom_id=None, all: bool = False, limit: int = 20,
                     status_change = "stale"
                     reason = f"source_{v['verdict']}: {v.get('reason', '')}"
                 else:
+                    # content-staleness re-fetch succeeded -> verdict is authoritative
+                    status_change = "supported"
                     reason = "supported"
         if status_change is None:
             # proxy-free fallback: возраст контента